I have tried I think every method known to get a seed up and running with as little root damage as possible. The method that I use now requires the use of small peat pots, the ones that look like an ice cream cone with a flat bottom. Into these cubes I place GERMINATION mix, not potting soil. I do not soak seeds, I just moisten the mix and place the seed 1/4" down and place the cube in a garden tray (if you have a lot of cubes) or plate, and place on a seedling heat mat. You can cover the cube by just laying Saran wrap loosely on top, keep moist (spray) In 3 day's I should have my seeds up. Then I transplant the cube into my final pot or container, maybe 3 day's after the seed sprouts. This way the tap root is never obstructed in growth, it grows right through the peat pot. For soil I place the plant in my 3 gal pots and in my drip system I use 4x4x4 Rockwool blocks with holes, in which I place the cube. I never remove the seedling from the cube, and the roots just grow right through it. You probably could place the seedling in the cube directly in any medium you use, coco, perlite, Hydroton, as the roots grow thru the peat pot, it does not dissolve so the germination mix does not wash away. I'm a big believer in uninterrupted root growth, and with my method there really isn't any repotting, or actual contact with the roots at all. Other methods require contact with the roots, one way or the other, unless you directly plant the seed in it's final spot, which can be a pain in the ass. This works for me very well, as I found that seeds LOVE germinating mix, as it is light and airy, and does not inhibit the growth in any way. To each their own.